1 /* SPDX-License-Identifier: BSD-3-Clause
2 * Copyright(c) 2010-2014 Intel Corporation
3 */
4
5 #include <stddef.h>
6 #include <errno.h>
7
8 #include <rte_memcpy.h>
9 #include <rte_ether.h>
10
11 #include "ip_frag_common.h"
12
13 /* Fragment Offset */
14 #define RTE_IPV4_HDR_DF_SHIFT 14
15 #define RTE_IPV4_HDR_MF_SHIFT 13
16 #define RTE_IPV4_HDR_FO_SHIFT 3
17
18 #define IPV4_HDR_DF_MASK (1 << RTE_IPV4_HDR_DF_SHIFT)
19 #define IPV4_HDR_MF_MASK (1 << RTE_IPV4_HDR_MF_SHIFT)
20
21 #define IPV4_HDR_FO_ALIGN (1 << RTE_IPV4_HDR_FO_SHIFT)
22
__fill_ipv4hdr_frag(struct rte_ipv4_hdr * dst,const struct rte_ipv4_hdr * src,uint16_t header_len,uint16_t len,uint16_t fofs,uint16_t dofs,uint32_t mf)23 static inline void __fill_ipv4hdr_frag(struct rte_ipv4_hdr *dst,
24 const struct rte_ipv4_hdr *src, uint16_t header_len,
25 uint16_t len, uint16_t fofs, uint16_t dofs, uint32_t mf)
26 {
27 rte_memcpy(dst, src, header_len);
28 fofs = (uint16_t)(fofs + (dofs >> RTE_IPV4_HDR_FO_SHIFT));
29 fofs = (uint16_t)(fofs | mf << RTE_IPV4_HDR_MF_SHIFT);
30 dst->fragment_offset = rte_cpu_to_be_16(fofs);
31 dst->total_length = rte_cpu_to_be_16(len);
32 dst->hdr_checksum = 0;
33 }
34
__free_fragments(struct rte_mbuf * mb[],uint32_t num)35 static inline void __free_fragments(struct rte_mbuf *mb[], uint32_t num)
36 {
37 uint32_t i;
38 for (i = 0; i != num; i++)
39 rte_pktmbuf_free(mb[i]);
40 }
41
42 /**
43 * IPv4 fragmentation.
44 *
45 * This function implements the fragmentation of IPv4 packets.
46 *
47 * @param pkt_in
48 * The input packet.
49 * @param pkts_out
50 * Array storing the output fragments.
51 * @param mtu_size
52 * Size in bytes of the Maximum Transfer Unit (MTU) for the outgoing IPv4
53 * datagrams. This value includes the size of the IPv4 header.
54 * @param pool_direct
55 * MBUF pool used for allocating direct buffers for the output fragments.
56 * @param pool_indirect
57 * MBUF pool used for allocating indirect buffers for the output fragments.
58 * @return
59 * Upon successful completion - number of output fragments placed
60 * in the pkts_out array.
61 * Otherwise - (-1) * <errno>.
62 */
63 int32_t
rte_ipv4_fragment_packet(struct rte_mbuf * pkt_in,struct rte_mbuf ** pkts_out,uint16_t nb_pkts_out,uint16_t mtu_size,struct rte_mempool * pool_direct,struct rte_mempool * pool_indirect)64 rte_ipv4_fragment_packet(struct rte_mbuf *pkt_in,
65 struct rte_mbuf **pkts_out,
66 uint16_t nb_pkts_out,
67 uint16_t mtu_size,
68 struct rte_mempool *pool_direct,
69 struct rte_mempool *pool_indirect)
70 {
71 struct rte_mbuf *in_seg = NULL;
72 struct rte_ipv4_hdr *in_hdr;
73 uint32_t out_pkt_pos, in_seg_data_pos;
74 uint32_t more_in_segs;
75 uint16_t fragment_offset, flag_offset, frag_size, header_len;
76 uint16_t frag_bytes_remaining;
77
78 /*
79 * Formal parameter checking.
80 */
81 if (unlikely(pkt_in == NULL) || unlikely(pkts_out == NULL) ||
82 unlikely(nb_pkts_out == 0) ||
83 unlikely(pool_direct == NULL) || unlikely(pool_indirect == NULL) ||
84 unlikely(mtu_size < RTE_ETHER_MIN_MTU))
85 return -EINVAL;
86
87 in_hdr = rte_pktmbuf_mtod(pkt_in, struct rte_ipv4_hdr *);
88 header_len = (in_hdr->version_ihl & RTE_IPV4_HDR_IHL_MASK) *
89 RTE_IPV4_IHL_MULTIPLIER;
90
91 /* Check IP header length */
92 if (unlikely(pkt_in->data_len < header_len) ||
93 unlikely(mtu_size < header_len))
94 return -EINVAL;
95
96 /*
97 * Ensure the IP payload length of all fragments is aligned to a
98 * multiple of 8 bytes as per RFC791 section 2.3.
99 */
100 frag_size = RTE_ALIGN_FLOOR((mtu_size - header_len),
101 IPV4_HDR_FO_ALIGN);
102
103 flag_offset = rte_cpu_to_be_16(in_hdr->fragment_offset);
104
105 /* If Don't Fragment flag is set */
106 if (unlikely ((flag_offset & IPV4_HDR_DF_MASK) != 0))
107 return -ENOTSUP;
108
109 /* Check that pkts_out is big enough to hold all fragments */
110 if (unlikely(frag_size * nb_pkts_out <
111 (uint16_t)(pkt_in->pkt_len - header_len)))
112 return -EINVAL;
113
114 in_seg = pkt_in;
115 in_seg_data_pos = header_len;
116 out_pkt_pos = 0;
117 fragment_offset = 0;
118
119 more_in_segs = 1;
120 while (likely(more_in_segs)) {
121 struct rte_mbuf *out_pkt = NULL, *out_seg_prev = NULL;
122 uint32_t more_out_segs;
123 struct rte_ipv4_hdr *out_hdr;
124
125 /* Allocate direct buffer */
126 out_pkt = rte_pktmbuf_alloc(pool_direct);
127 if (unlikely(out_pkt == NULL)) {
128 __free_fragments(pkts_out, out_pkt_pos);
129 return -ENOMEM;
130 }
131
132 /* Reserve space for the IP header that will be built later */
133 out_pkt->data_len = header_len;
134 out_pkt->pkt_len = header_len;
135 frag_bytes_remaining = frag_size;
136
137 out_seg_prev = out_pkt;
138 more_out_segs = 1;
139 while (likely(more_out_segs && more_in_segs)) {
140 struct rte_mbuf *out_seg = NULL;
141 uint32_t len;
142
143 /* Allocate indirect buffer */
144 out_seg = rte_pktmbuf_alloc(pool_indirect);
145 if (unlikely(out_seg == NULL)) {
146 rte_pktmbuf_free(out_pkt);
147 __free_fragments(pkts_out, out_pkt_pos);
148 return -ENOMEM;
149 }
150 out_seg_prev->next = out_seg;
151 out_seg_prev = out_seg;
152
153 /* Prepare indirect buffer */
154 rte_pktmbuf_attach(out_seg, in_seg);
155 len = frag_bytes_remaining;
156 if (len > (in_seg->data_len - in_seg_data_pos)) {
157 len = in_seg->data_len - in_seg_data_pos;
158 }
159 out_seg->data_off = in_seg->data_off + in_seg_data_pos;
160 out_seg->data_len = (uint16_t)len;
161 out_pkt->pkt_len = (uint16_t)(len +
162 out_pkt->pkt_len);
163 out_pkt->nb_segs += 1;
164 in_seg_data_pos += len;
165 frag_bytes_remaining -= len;
166
167 /* Current output packet (i.e. fragment) done ? */
168 if (unlikely(frag_bytes_remaining == 0))
169 more_out_segs = 0;
170
171 /* Current input segment done ? */
172 if (unlikely(in_seg_data_pos == in_seg->data_len)) {
173 in_seg = in_seg->next;
174 in_seg_data_pos = 0;
175
176 if (unlikely(in_seg == NULL))
177 more_in_segs = 0;
178 }
179 }
180
181 /* Build the IP header */
182
183 out_hdr = rte_pktmbuf_mtod(out_pkt, struct rte_ipv4_hdr *);
184
185 __fill_ipv4hdr_frag(out_hdr, in_hdr, header_len,
186 (uint16_t)out_pkt->pkt_len,
187 flag_offset, fragment_offset, more_in_segs);
188
189 fragment_offset = (uint16_t)(fragment_offset +
190 out_pkt->pkt_len - header_len);
191
192 out_pkt->l3_len = header_len;
193
194 /* Write the fragment to the output list */
195 pkts_out[out_pkt_pos] = out_pkt;
196 out_pkt_pos ++;
197 }
198
199 return out_pkt_pos;
200 }
201